Heat a large skillet over medium-high heat with the olive oil. Once hot, add the chicken pieces and cook until browned and crispy all over, about 10 minutes. Make sure to stir around every once in a while. Add the chopped onions and garlic and cook for another 5 minutes to soften them. Season with a bit of salt and pepper. Add the sliced mushrooms and cook until browned, about 5 minutes.
Add the flour over the veggies and chicken and stir to evenly coat. Slowly stream in the chicken broth and allow to thicken. Season with the rest of the salt and pepper. Cook for about 10 minutes on low to blend the flavors. Garnish with the sliced scallions and serve with rice. Enjoy!